Search Results (3,708)

Natural pumice can reduce the self-weight of concrete, but its high porosity, high water absorption, and weak interfacial bonding tend to limit the strength and durability of lightweight aggregate concrete. To address this issue, this study proposes a method for preparing and applying reinforced pumice lightweight aggregates, namely, using nano-SiO₂-modified fly ash to construct a nanocomposite material at the micro-interface for the reinforcement treatment of natural pumice aggregates, and reveals the mechanism by which this treatment enhances the performance of lightweight aggregate concrete. Through aggregate performance tests, compressive strength tests, XRD, SEM, and freeze–thaw cycle tests, the effects of the reinforced pumice aggregate on the performance of lightweight concrete were systematically investigated. The results show that after the reinforcement treatment, the water absorption of the pumice aggregate decreases by 17.6%, and the cylinder compressive strength increases by 34.3%. As the replacement ratio of reinforced pumice increases, both the early-age and later-age compressive strengths of the concrete continuously improve. When all the pumice aggregate is reinforced, the 3 d and 28 d compressive strengths increase by 35.1% and 33.44%, respectively. Meanwhile, the reinforced pumice effectively improves the interfacial bonding between the aggregate and the cement paste, reducing the width of the interfacial transition zone by 32%, enhancing the matrix compactness, and delaying crack propagation. The study demonstrates that the reinforced pumice aggregate possesses favorable characteristics, not only effectively improving the mechanical properties and freeze–thaw resistance of lightweight concrete but also providing a new technical pathway for the high-performance utilization of porous lightweight aggregates, offering a reference for the resource utilization of industrial solid waste and engineering applications in cold regions. Full article

Acoustic emission (AE) and digital image correlation (DIC) techniques enable real-time capture of damage signals and full-field deformation at anchored rock–concrete interfaces under shear loading, which is critical for quantitatively characterizing freeze–thaw (F-T) degradation and preventing geological disasters in cold regions. This study synchronously monitored full-shear-process AE signals using a broadband AE system (150 kHz resonant frequency, 5 MS/s sampling) and captured high-precision full-field deformation via a 5-megapixel monocular DIC system (25 fps). F-T cycle and direct shear tests were conducted on sandstone–concrete anchored specimens with varying F-T cycles and anchor depths to investigate their effects on shear mechanical properties, AE characteristics and failure modes. Results show that AE peak ring count first decreases by 44.9% then increases by 56.5%, while cumulative ring count exhibits a three-stage evolution. Shear crack proportion first decreases then increases, with tensile failure remaining dominant throughout. DIC reveals that F-T cycles shift failure from crack propagation to surface delamination and interface slip, while different anchor depths induce distinct failure patterns. This study confirms that AE and DIC can accurately characterize F-T degradation, providing a reliable non-destructive monitoring method for cold-region anchorage engineering. Full article

Desertsand concrete (DSC) is a sustainable alternative to natural river sand; however, its application in cold regions is restricted by inadequate crack resistance and freeze–thaw durability. This study investigates the freeze–thaw performance of steel–polypropylene hybrid fiber-reinforced desert sand concrete (SPHF-DSC), with emphasis on durability enhancement and service life prediction. A three-factor, three-level orthogonal experimental design was employed to evaluate the effects of desert sand replacement ratio (DSR), steel fiber (SF) content, and polypropylene fiber (PPF) content on mass loss, relative dynamic elastic modulus, and compressive strength under 25–100 freeze–thaw cycles. The results demonstrate that hybrid fiber reinforcement significantly improves freeze–thaw resistance due to the synergistic interaction between SF and PPF. After 100 cycles, the mass loss of all specimens remained within a narrow range of 0.65% to 0.73%, and the relative dynamic elastic modulus retention stayed above 90%. The optimal mixture (DSR = 30%, SF = 2%, PPF = 0.05%) exhibited superior frost resistance with the lowest deterioration indices among all groups. A freeze–thaw damage model based on damage mechanics was established and validated ($R^2$ > 0.96), enabling prediction of a service life exceeding 38 years under typical cold-region climatic conditions. These findings provide a durability-oriented design reference for the engineering application of DSC in cold-region infrastructure. Furthermore, the utilization of local desert sand reduces transportation energy consumption and promotes the sustainable development of energy infrastructure. Full article

This study investigates the durability of Class C/Class F fly ash geopolymer mortars with varying ash-to-sand ratios under freeze–thaw cycles, MgSO₄ exposure, and their combined action. The results showed that geopolymer specimens with ash-to-sand ratios of 1:1.4 and 1:1.6 exhibited excellent durability under individual freeze–thaw or MgSO₄ attack. After 60 freeze–thaw cycles, the mass losses ranged from 1.44% to 3.19%, while the residual compressive strength remained between 103.7% and 107.0% of the initial value. After 90 days of MgSO₄ exposure, the mass loss was limited to 0.28–1.40%, and the residual strength increased significantly to 147.5–159.8%. However, the combined effect of freeze–thaw cycles and MgSO₄ corrosion was not simply additive. Under combined degradation, mass loss increased markedly to 7.29–9.28% after 60 cycles, while residual strength declined to 42.6–53.7%. The ash-to-sand ratio significantly influenced the pore size distributions. A direct relationship was observed among reaction products, microstructure, and freeze–thaw resistance. These findings provide insight into the durability mechanisms of fly ash geopolymer mortars and support their application in cold-region infrastructures. Full article

This study investigates the effect of polyvinyl alcohol (PVA) on the performance of natural hydraulic lime (NHL)-based repair mortars used in historical building restoration. Mortars were prepared with varying PVA dosages (0.25%, 0.5%, 0.75%, and 1.0%) to evaluate their impact on physical, mechanical, and durability properties, including setting time, strength, water absorption, shrinkage, and resistance to freeze–thaw and sulfate attack. The results demonstrate that PVA significantly enhances bonding strength, reduces water absorption, and improves durability, with optimal performance observed at a 0.5% PVA dosage. Microstructural analysis showed that PVA forms a cohesive film, reinforcing the mortar’s structure. These findings suggest that PVA can enhance the performance of NHL-based mortars, offering significant potential for historical building restoration, particularly under challenging environmental conditions. Full article

Freeze–thaw damage significantly reduces the performance and durability of airport pavements in cold regions. Traditional assessment methods, such as the F300 freeze–thaw test, are time-consuming and hinder rapid optimisation of mix design. In addition, previous studies have mostly relied on long-term laboratory testing and have evaluated phase-change concrete (PCC) independently, without considering synergistic effects. These approaches lack fast, synergy-aware predictive capability and interpretable tools for mix proportion design, resulting in a gap between laboratory research and practical engineering applications. To address this issue, this study proposes an intelligent and explainable framework for predicting freeze–thaw damage and guiding mix design of steel fibre-reinforced phase-change concrete (SF–PCC). A boundary-controlled experimental programme was first conducted, varying steel fibre (SF) content from 0 to 1.2% and phase-change material (PCM) content from 0 to 12% under fixed mixture conditions. The freeze–thaw test results were recorded sequentially and used to construct a supervised learning dataset. Then, an XGBoost model was developed to predict two key durability indicators: relative dynamic modulus of elasticity (RDEM) and mass loss. SHAP (SHapley Additive exPlanations) analysis was further applied to quantify feature importance and interaction effects. The model achieved high predictive accuracy (R² = 0.9938 for mass loss and R² = 0.9935 for RDEM) under controlled experimental conditions. After 300 freeze–thaw cycles, the reference mix exhibited an RDEM of 61.2%, while optimised configurations showed improved performance. The economical design (9% PCM + 0.9% SF) achieved an RDEM of 66.8%, and the high-performance design (12% PCM + 1.2% SF) reached 72.6%. These results demonstrate that the proposed framework can effectively enhance durability and support rapid preliminary decision-making. The framework significantly accelerates freeze–thaw performance evaluation by enabling near-instant prediction and serves as an efficient supplementary tool for mix design optimisation alongside conventional laboratory testing. It also provides interpretable, data-driven insights for the design of freeze–thaw-resistant airport pavement concrete in cold regions. Full article

The growing demand for sustainable construction has highlighted the need to effectively utilize solid waste materials in concrete production, yet achieving satisfactory workability, strength, and durability simultaneously remains challenging. A multi-parameter mix-design methodology is proposed for solid-waste-based self-compacting concrete (SCC). This method couples minimum water demand, control of paste film thickness, and multi-performance balancing. The ternary solid-waste powder system (silica fume, fly ash, and supersulfated solid-waste-based cement) was first optimized through minimizing water demand to achieve maximum packing density. The resulting composition was then blended with varying dosages of ordinary Portland cement (OPC) to form the final cementitious binder. Aggregate gradation was proportioned to minimize voids, and paste volume was determined using an equivalent-paste-film-thickness model. Under comparable mixture conditions, SCC with OPC contents of 70–40 wt.% and paste film thicknesses of 2.0–2.6 mm was evaluated for fresh performance, compressive strength, freeze–thaw resistance, and material cost. Mixtures with a paste film thickness of 2.4 or 2.6 mm satisfied the self-compactability criterion—the mix with 50 wt.% OPC and a paste film thickness of 2.4 mm showed the best overall performance balance, achieving higher 28 d strength than higher-OPC mixtures while improving freeze–thaw resistance and reducing cost. Results from TGA, XRD, ATR–FTIR, and SEM–EDS analyses indicated enhanced calcium hydroxide (CH) consumption, increased formation of C-(A)-S-H and ettringite, and a denser interfacial transition zone (ITZ), supporting the proposed multi-objective design approach. While the framework was validated for a specific ternary binder system, it provides a reproducible proportioning strategy applicable to a broader range of solid-waste-based concrete systems, with potential for extension to other waste streams and exposure conditions, thus supporting the development of more resource-efficient and environmentally sustainable concrete. Full article

Date palm (Phoenix dactylifera L.) production relies on the availability of viable and physiologically active pollen during female flowering, making pollen storage an important strategy to overcome flowering asynchrony and ensure effective artificial pollination. In this study, we systematically reviewed and quantitatively synthesized the effects of pollen storage conditions on pollen physiological quality and reproductive performance in date palm. Following PRISMA guidelines, 22 experimental studies were identified in the qualitative synthesis, and comparable quantitative datasets were used for meta-analysis. Acetocarmine staining, the most commonly used method for assessing pollen stainability across studies, was selected as the standardized indicator of pollen stainability. Multilevel random-effects meta-regression models were applied to evaluate temporal deterioration patterns over storage periods of up to 24 months, while standardized forest plot meta-analyses were used to estimate pooled effects after 12 months of storage. The results revealed a strong temperature-dependent decline in pollen physiological quality. Acetocarmine stainability declined by −6.41, −3.10, −2.62, and −2.24% month⁻¹ under ambient, refrigerated, mild freezing, and moderate freezing conditions, respectively, whereas germination declined by −6.77, −1.86, −3.14, −1.09, and −1.05% month⁻¹ under ambient (23–25 °C), refrigerated (4–5 °C), mild freezing (−5 °C), moderate freezing (−20 °C), and deep freezing (−80 °C) conditions, respectively. After 12 months of storage, stainability, germination, and fruit set were significantly reduced relative to fresh pollen. In contrast, pollen storage had no significant effect on final fruit weight, suggesting that pollen deterioration primarily affects fertilization success rather than subsequent fruit development. The available evidence suggests that low-temperature storage represents the most effective strategy for preserving date palm pollen functionality. Refrigerated storage around 4 °C appears to provide a reliable and accessible option for short- to medium-term pollen preservation, whereas freezing conditions may be advantageous for longer storage periods when moisture control and thawing procedures are properly managed. Full article

As a typical industrial solid waste-based concrete material, activated coal gangue cementitious concrete is prone to the freeze-thaw cycle in cold-region engineering applications, leading to durability degradation that severely limits its service performance. In this paper, freeze-thaw cycle tests were designed to reveal the influence of different ratio designs on the freeze resistance of materials. Scanning electron microscopy and nuclear magnetic resonance spectroscopy were employed to observe the microstructural changes in the internal pores of activated coal gangue cementitious concrete after freeze-thaw degradation. The optimal replacement ratio for activated coal gangue powder was analyzed. The results showed that, as the number of freeze-thaw cycles increased, the pore structure within the activated coal gangue cemented concrete deteriorated significantly, though the degree of deterioration varied. With the gangue powder content increasing, both the number of pores and porosity within the concrete initially decrease and then increase. According to the test results, when the activated coal gangue powder content was 35% in the concrete mix, the freeze-thaw resistance performance was optimal. This mixture maintained a good pore structure and superior porosity, indicating that the concrete with 35% activated coal gangue powder content was the best mix design. The result provides a reference for enhancing the freeze-thaw resistance of activated coal gangue cementitious concrete in cold environments. Full article

Soil erosion in mountain environments is governed by the interaction of climatic drivers, surface conditions, and geomorphic connectivity. Recently, disturbance by large herbivores has been recognized as a potentially important but poorly quantified geomorphic driver. However, the combined effects of freeze–thaw processes and ungulate disturbance on sediment production remain unclear. This study provides quantitative field-based evidence linking deer activity to hillslope sediment flux in a montane forest catchment in central Japan. A six-year dataset (2019–2025), including climatic conditions, deer detections from camera traps, understory vegetation cover, and hillslope sediment flux (<9.5 mm) was analyzed. Multiple regression analysis was conducted using daily sediment flux as the response variable and maximum 1 h rainfall, freeze–thaw frequency, and daily deer detections as explanatory variables. The results showed that deer detections had a significant positive effect on sediment flux, whereas rainfall intensity and freeze–thaw frequency did not exhibit strong independent effects. Particle-size analysis further indicated that eroded sediment was markedly coarser than the surface soil, suggesting that short-term climatic drivers alone did not control sediment transport. These findings demonstrate that biotic disturbance by large herbivores can play a dominant role in hillslope sediment flux under cold, high-elevation conditions by modifying surface conditions and sediment connectivity. From a sustainability perspective, these results highlight the importance of managing deer populations to maintain ecosystem stability, prevent land degradation, and support sustainable forest and watershed management under changing environmental conditions. Full article

Due to the high water absorption of coal gangue aggregate, concrete prepared with a high content of this material exhibits a significantly reduced service life under freeze–thaw conditions. This study evaluates the frost resistance of gel-enhanced coal gangue aggregate concrete modified by incorporating nano-SiO₂ and polypropylene fibre (PPF) to generate more C-S-H gel and form a dense structure with different dosages of air-entraining agent (0, 0.004%, 0.008%, 0.012%, and 0.016%). The research results show that when the admixture content is 0.012%, the concrete still exhibits excellent frost resistance after 100 freeze–thaw cycles. The mass loss is only 4.7%, compressive strength loss is 37%, and dynamic elastic modulus loss is 39%, while the specimen maintains the best apparent integrity. In addition, the capillary water absorption rate, initial capillary water absorption rate, and cumulative water absorption all reach their lowest values under this condition, indicating optimal frost resistance performance. Finally, through regression analysis, a highly accurate predictive model for capillary water absorption was established, providing a theoretical basis for further research on the durability and frost resistance of coal gangue aggregate concrete. Full article

Background: B7-H3, a type I transmembrane glycoprotein belonging to the B7 superfamily, is an attractive target for antitumor therapies. B7-H3 demonstrates aberrant overexpression in various types of solid tumors while showing limited and low expression in normal human organs. Various types of treatment targeting B7-H3 have been reported. Among these treatments, antibody–drug conjugates (ADCs) have shown potent activity, and several clinical trials, including DS7300a and MGC018, are currently ongoing. Methods: Here, we constructed CD276-8 ADC, composed of the anti-B7-H3 antibody CD276-8 with moderate affinity, an enzymatically cleavable tetra-peptide-based linker and DXd. Characteristics, including in vitro binding affinity and internalization activity, were assessed by bio-layer interferometry (BLI), flow cytometry and high content analysis (HCA). The cytotoxicity of CD276-8 ADC was evaluated in cell lines expressing B7-H3. Pharmacokinetic profiles and antitumor activity were evaluated in mouse models in vivo. Finally, the developability of CD276-8 ADC was assessed with plasma stability, accelerated stability and freeze–thaw studies using LC-MS and HPLC. Results: Characterization in vitro demonstrated the moderate affinity and acceptable internalization activity of CD276-8 ADC. In addition, CD276-8 ADC exhibited potent antitumor activities in B7-H3-positive cell line-derived xenograft (CDX) models with acceptable pharmacokinetic profiles, although it showed less potent cytotoxicity in various cell lines in vitro, indicating acceptable developability. Conclusions: We developed CD276-8 ADC, a B7-H3-targeting ADC with moderate affinity, which delivers the TOP1 inhibitor DXd. This design combined moderate affinity and acceptable pharmacokinetics, resulting in potent antitumor efficacy in vivo. Our study suggests that affinity optimization could be a useful consideration for enhancing ADC efficacy, positioning CD276-8 ADC as a promising therapeutic for B7-H3-expressing solid tumors. Full article

Improving the energy efficiency of historic field stone masonry buildings often requires internal insulation, as external insulation is frequently restricted by heritage and architectural constraints. Internal insulation, however, alters the hygrothermal behavior of massive masonry walls and may increase moisture-related risks. This study assesses the hygrothermal performance of an internally insulated historic field stone masonry wall under past and projected future climatic conditions using long-term transient simulations. Coupled heat and moisture transfer simulations were performed with the DELPHIN software for an uninsulated reference wall and an internally insulated configuration. The analyses accounted for wind-driven rain, masonry heterogeneity, and variations in inner core composition. Past conditions were represented by a continuous 20-year measured climate dataset, while future conditions were evaluated using regional late-century climate projections (RCP2.6 and RCP8.5). Hygrothermal performance was evaluated based on moisture mass density, freeze–thaw exposure, and mold-relevant temperature–relative humidity conditions at predefined evaluation points within the wall. The results show that moisture accumulation develops gradually and cannot be reliably captured by short simulation periods. Internal insulation redistributes moisture-related risks within the wall rather than fundamentally altering the seasonal moisture regime. Freeze–thaw exposure occurs under all investigated climates, while mold-relevant humidity conditions persist at interior-adjacent locations. The findings demonstrate the importance of multi-year hygrothermal analyses when assessing moisture-related risks in internally insulated historic masonry walls. Full article

Soil organic carbon (SOC) is essential for ecosystem stability and long-term carbon storage in alpine grasslands, yet the relative importance and interactions of hydrothermal and biotic controls remain poorly understood at regional scales. In this study, we quantified surface SOC (0–20 cm) across the Yellow River Source Region (YRSR) on the northeastern Tibetan Plateau, a climate-sensitive alpine headwater system characterized by strong hydrothermal gradients and freeze–thaw dynamics. Field-based SOC measurements were integrated with multi-source remote sensing and reanalysis data that describe thermal conditions, moisture processes, vegetation productivity, soil properties, topography, and human influence. A two-step screening approach was applied using Boruta and variance inflation factor filtering, followed by modeling with random forest. The model outputs were interpreted using Shapley Additive Explanations (SHAP). SOC displayed significant spatial heterogeneity across the region. Vegetation productivity, moisture availability, and thermal conditions were identified as the dominant nonlinear drivers of SOC variation. Moisture availability emerged as a central regulator of SOC, affecting it both directly and indirectly through vegetation productivity and thermal conditions. These findings underscore the importance of hydrothermal stability in sustaining soil carbon stocks and provide a quantitative basis for adaptive grassland management under a warming climate. Full article

Large-scale pavement maintenance generates substantial amounts of reclaimed base course material (RBM), whose high-value reuse presents a critical challenge. Although cement is commonly used for stabilization, its high carbon footprint and shrinkage issues limit sustainability. This study proposes a 100% solid waste-based cementitious material (SWC) as an alternative stabilizer for pavement base layers containing high proportions of RBM. A comparative investigation was conducted between SWC-stabilized RBM (SSRBM) and ordinary Portland cement-stabilized RBM (CSRBM) regarding key road performance indicators. The results indicate that with 100% RBM, the 7-day compressive strength of SSRBM containing 4% SWC reaches 1.88 MPa, meeting the Chinese specification JTG/T 5521-2019. By incorporating 15% natural coarse aggregate, this strength can be increased by 35.4%. Furthermore, SSRBM demonstrates superior freeze–thaw resistance, with a freeze–thaw-retained unconfined compressive strength ratio of 93.9%, compared to 89.6% for CSRBM, and exhibits a lower drying shrinkage coefficient. Carbon emission analysis shows that the emissions per cubic meter of SSRBM are approximately 73% lower than those of CSRBM, presenting a viable and environmentally advantageous alternative for sustainable pavement construction. Full article